The Booroolong frog project in the Namoi Catchment represents an environmental investment to protect the species and around 10.7 kilometres of its habitat in the catchment. The project’s benefit-cost ratio (BCR) of 8.6 indicates that the benefits outweigh the costs by a significant margin. The measures introduced by landholders, at relatively low cost, should therefore result in a significant return on investment upon project completion in 10 years time. The benefits are estimated using a choice modelling study which was recently developed for the valuation of investment in natural resource management in the Namoi Catchment. As this is a largely ex ante cost-benefit analysis, the BCR is subject to uncertainty associated with assumptions which had to be made for some variables. However, sensitivity analysis indicates that the project benefits outweigh the costs by a significant margin even under conservative conditions.